Re: emacs rendering comparisson between emacs23 and emacs26.3

[Eli Zaretskii]

> Cc: address@hidden, address@hidden, address@hidden, address@hidden,
>  address@hidden
> From: Dmitry Gutov <address@hidden>
> Date: Sun, 5 Apr 2020 21:55:39 +0300
> 
> On 05.04.2020 21:23, Eli Zaretskii wrote:
> > No, redisplay-dont-pause wasn't supposed to help when redisplay cannot
> > keep up.  It is for the opposite use case: when redisplay is so slow
> > it slows down processing of your commands, like typing, for example.
> > You'd then set it to nil to speed up command processing, while giving
> > up correct display at all times.
> 
> What's the difference between redisplay being slow and it being unable 
> to "keep up"? I don't understand, sorry.

That's not the important difference.  The important difference is that
you want the input processed faster, without waiting for slow
redisplay.

> And in this case, IIUC, jit-lock is part of redisplay. And it's slow 
> enough for this to be noticeable.

It isn't jit-lock that's slow, it's the fontification functions it
calls.